Potentially harmful pollutants are often produced within a crankcase of an internal combustion engine during operation. These pollutants are present in combustion waste gases, known as "blow-by" gases, that leak past the engine piston rings into the crankcase, where they mix with air that usually includes oil vapor from the engine.
These gases must be allowed to leave the crankcase, to prevent oil vapor from leaking back past the piston rings. The gases increase pressure in the crankcase if left therein. The excess pressure can cause seals to leak and affects normal engine operation in a negative manner.
If the blow-by is merely vented through a road draft tube for example into the atmosphere, the pollutants contribute to air pollution, and engine oil is lost as well.
An alternative approach in handling blow-by has been to pass it through a positive crankcase ventilation (PCV) valve into the intake manifold for recombustion in the engine's combustion chamber, in response to a changing pressure within the crankcase. This can cause different pollutants to be generated by the engine, which also contributes to air pollution. In addition, diverting blow-by into the intake system causes the oily mixture to stick along the walls of the intake manifold and head. Additionally, the oily mixture can cause valve fouling.
Various solutions have been tried. One approach is to route blow-by gases through a filter to remove oil in the oil vapor and other pollutants, such as taught in U.S. Pat. No. 5,722,376 to Sweeten for example. The filter must be periodically changed, however, and oil is lost when the used filter is discarded.
This invention is directed to addressing one or more of the above concerns.